The principal goal of this project is to adapt the "Phenotype MicroArray[TM]" ("PM") technology of Biolog, Inc (Hayward, CA) for fastidious and microaerophilic bacterial species, with special emphasis on those important in human disease. PM technology allows efficient, sensitive characterization of thousands of physiologic and phenotypic properties of microbial cells. The Phase I studies proposed here will focus on strains of the gastric pathogen Helicobacter pylori (Hp) (implicated in peptic ulcer disease and gastric cancer), and the intestinal pathogen Campylobacter jejuni (Cj) (a very common cause of gastroenteritis, and rheumatoid arthritis, and also (with some strains) of an autoimmune induced peripheral nerve degeneration and paralysis - Guillain Barre syndrome). Cj and Hp are each genetically diverse. Cj is weakly clonal in population genetic structure, whereas Hp is considered non-clonal, but exhibits striking geographic differences in gene pools, especially with strains of East Asia vs. Europe and the Americas. This Phase I STTR project has two experimental Aims. First: To refine, optimize, and implement a PM technology testing protocol for robust analysis of representative Hp and Cj strains. This will make testing of Hp and Cj strains available to the scientific research community, either through PM Kits or PM Services. Second: To transfer this technology to Berg's lab, where it will be beta site tested and used to study a range of Hp and Cj strains chosen primarily for their particular disease associations and to assess if such disease associations are linked to metabolic differences or other PM-detected phenotypic traits. With Hp, the effects of human gastrin (a reported stimulator of Hp growth, and possible signal of Hp entry into the gastric mucosa) on PM profiles will be determined. With Cj, PM profiles of representative strains will be scored at 37C vs. 42C, to assess if thermal signaling might be used by Cj to adapt to different hosts (human vs. chicken). In Phase II the PM methodology will be implemented for representative strains of other Helicobacter and Campylobacter species, and also for other genera of fastidious pathogens.